ML20050C207
| ML20050C207 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 03/23/1982 |
| From: | Mcgaughy J MISSISSIPPI POWER & LIGHT CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, AECM-82-L04, AECM-82-L4, NUDOCS 8204080280 | |
| Download: ML20050C207 (4) | |
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j 4 E MISSISSIPPI POWER & LIGHT COMPANY Helping Build Mississippi
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P. O. B O X 16 4 0. J A C K S O N. MISSISSIPPI 39205
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J AMES P. McGAUGHY, JR.
March 23, 198 asstSTANT VICE Paf 86 DENT
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Of fice of Inspection & Enforcement
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g U. S. Nuclear Regulatory Commission eu-s -- -
Region 11
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101 Marietta Street, N.W.
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Attention:
Mr. J. P. O'Reilly, Regional Administrator 4
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Dear Mr. O'Reilly:
SUBJECT:
Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-416/417 File 0260/15525/15526 PRD-81/53, Final Report, Pneumatic Logic for the Delaval Stendby Diesel Generators AECM-82/104 On December 31, 1981, Mississippi Power & Light Company notified Mr. R.
Butcher, of your of fice, of a Potentially Reportable Deficiency (PRD) at the Grand Gulf Nuclear Station (CGNS) construction site.
The deficiency concerns the pneumatic logic of the Delaval Standby Diesel Generators.
Based on our investigation into this matter, the determination has been made that this deficiency is not reportable under the provisions of either 10CFR50.55(e) or 10CFR21.
Our Final Report is attached.
Yours truly, J. P. McGaughy, Jr.
ACP:dr ATTAC~ MENT cc:
See page 2 K ohhh6 LeFFICIAL pgpy PDR i
i Member Middle South Ut ~: ties System J[
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Mr. J. P. O'Reilly AECM-82/104 NRC Page 2 cc': Mr. N. L. Stampley Mr. R. B. McGehee -
Mr. T. B. Conner
' Mr. Richard C. DeYoung, Director Office of -Inspection & Enforcement
-U. S. Nuclear Regulatory Cociss10n i
Washington, D.C. 20555 Mr. G. B. Taylor South;Miss. Electric Power Association P. O. Box 1589 Hattiesburg, MS 39401 4
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Attechatnt to AECM-82/104 Pags 1 of 2 FINAL REPOR( AR PRD-81/53 I.
Description of the Deficiency The Standby Diesel Generator pneumatic logic is to be designed such that the engines will automatically shutdown on either low lube oil pressure with a 2-out-of-3 logic or high crankcase pressure with a 2-out-of-3 logic. However, due to the two logic lines being tied into a common line, it is possible that the. engines could be shutdown on a 2-out-of-6 logic with 1-out-of-3 f rom both the low lube oil logic and the high crankcase pressure initiating the trip.
The plant system affected by this deficiency is the Standby Diesel Generator System - ?7 5.
This cited deficiency is applicable to both Unit I and Unit
'2.
The cause is related directly to vendor design.
II.
Analysis of Safety Implications Our Architect / Engineer has determined that.this deficiency presents no adverse affects on the safety of operations of the power plant. The rationale for this position is that the cited condition, had it remained uncorrected, the probability of a generator trip, on a combined 1-out-of-3 logic occuring, is extremely remote. Although the condition could affect the reliability, the overall effect on the generator required operability is insignificant to create a safety concern.
The condition does not violate either design ~ specification requirements or NRC regulations.
In their response to our Architect / Engineer, Delaval has stated: "There is no defect with the equipment and the condition is unique with this installation".
Therefore, based on this rationale, the determination has been made that this deficiency is not reportable under the provisions of 10CFR50.55(e) or
.10CFR21.
III. Corrective Actions Taken The corrective action which has been taken was to delete the high crankcase pressure trip during the emergency mode of operation, but retain the alarm indications,,both visual and audible. - During the test mode of operation, the shutdown function would be retained as well as the alarms.
The high crankcase pressure _ shutdown is an unnecessary function. The high crankcase pressure shutdown is initiated only af ter a crankcase explosion takes _ place. The shutdown is not to prevent an explosion, but to allow the engine to _ be inspected for. the cause of the explosion. Normally, a' crankcase explosion will not; incapacitate an engine. The explosion is caused by an
. local hotspot igniting an explosive mixture of oil and gases and is instan-
'taneous. The local hotspots can be caused by high bearing' temperatures.
There are high bearing temperature detectors equipped on the engines.
The
- bearing temperatures are monitored by alarms and in the test mode would also
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shutdown the engine.-
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Attachm3nt to AECH-82/104 aj
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Pagn 2 of 2 Drawings have been revised to reflect this change.
Corrective actions are complete for Unit 1 and corrective actions for Unit 2 will be completed af ter the construction of Unit 2 is resumed.
The manufacturer, Transamerica Delaval, has determined that this deficiency was an isolated occurrence. Therefore, actions to preclude recurrence are not required..
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